John k



April 1, 1924.

l -J. K. NQRTHRQR ELECTRIC HEATER INVENTOR 6H/v /l/affr/f/fof BY www@ ATTORNEYS u if..

WITNESS 7 Patented Apr. 1, 1924.

UNITED STATES JOHNK. Non-Timor, or SANTA BARBARA, oALIro'amA ELECTRIC HEATER.

Appncaan sled January 9, 1922,. serial no. 528,049.

To all flo/tom t may concern.' A

'Be it lmown that l, JOHN K. NoRTHnor, a citizen of the United. States of America, and a resident ofthe city of Santa Barbara, county of Santa Barbara, and State of California, have invented a new and useful Electric Heater7 of which the following is a spec'- iication. i

My inventionV relates to 'electric .heaters and particularly to that type known as immersion heaters.'

One of the objects of they invention isto provide an electric heater which may be used lwith a hot water bottle to heat the contents of the bottle to a predetermined temperature Y and Vthen maintain that temperature substantially constant. Another object' of .theV invention is to provide an electricI heater of the character recited which is of 'simple construction and capable ofbeingmanufactured atlo'wcosts'.' 'A

My invention possesses other objects and features of advantage, some of which, with ythe foregoing, will'be set forth in the following description of my invention.' Itis to be understood that I do not/limit myself to the showing made by thesaid description, as I may adopt variant forms of the inven- -tion within the scope of the claims. l

Referring to the drawings: Fig 1 is a sectional view on anenlarged lscale takenlongitudinally thru the' heater. Fig. 2 is an elevation of the'upperportion of my heater. Fig. 3 is a sectional view, the `plane of section being indicatedby the line 3--3 of Fig.

1 Fig. 4 is a sectional View thru the upper portion of my device, the plane of section be ing indicated bytheline 4 4 of Fig. 2.

`In general terms the device of my invention comprises a suitably protected and insulated heating element of a shape adapting it to be inserted into the filling aperture of a hot water bottle. .Means comprising a stopper for the bottleare provided in which the tube is mounted and heat responsive means .are also provided for regulating the amount of energizing current suppliedto the heating elementin accordance with the tem perature of the fluid in which the heating element is immersed lto the end that the fluid in the bottle mayV be maintained at substantially ay constant temperature.

More particularly my device` comprises a tube 2 terminating Aat its lower end in a bulb 3 closed' by the cap 4 which is preferably permanently soldered or otherwise suitably secured to the bulb. The bulb which is connected to the tube vby the neckl encloses aV chamber 6 which` contains a quanttyof volatile fluid, such as ether, introduced intothe chamberrthru al vfillingaperture normally closed by the screw 7;

Art 'the opposite end, ,thelt'ube terminates in a hollow head formed ofbakelitefor com?V Y para-ble non-conducting y material comprising the slmllarfront and rear parts 8 an'd9V respectively, which are preferably clamped together and'about Vthe endof the tube* by means of screwsll located 'at suitable points in the head'part. When thehead Vis assembled upon the tube, a thin coating of cement is preferably applied tothe engaged surfaces vtube 13 passes thru the larger portion but is 'exposed about its surface-in that Vportion which'extends beside the smaller portion of the tube'2. ,Preferably thetube 2 `together with theintegrally formed' bulb 3 is die cast and the pressure transfertube 13 is preferably enclosed within. thev mold in proper positionwhen the casting ism'ade."A f

The main tube 2 is formed with avflange 14 between which and the adjacent end of the head is rotatablymounted the Vstopper 'so to make the jointtight andtc prevent the complete sepa-ration of the parts inthe l per 16 is also Provided with an interrupted Vflange 21 which preferably surrounds the lower portion of the head and` providesa grip with which the stopper may be turned 'to its seat. Below the flange 14 is a rubber washer 22 which completes the stopper and lprevents leakage of the contents of the bottle lV when it is pressed to its seatin the lower portion of the filling aperture ofthe hot ,water bottle. The washer 22 is normally secured 'in place by the metallic Washer 23 which is notchedto pass the Studs 24 formed on the tube and which are provided for the purpose of retaining the protective casing 26 which surrounds the main tube 2 as indicated in Fig. 1. The casing is preferably apertured to give free access of the iluid in which the device is immersed to the surface of the main tube 2 and the exposed portion 0I" the tube 18. rThe casing is prefe-rablj/J formed from a fiat sheet of material and slightly smaller than the diameter ot the part with which it is engaged. The upper portion of the sheet is torni ed with L-ormed notches 27 as shown best in the lower part of Fig. 4;, and when pressed into place on the main tube the studs 24 prevent axial movement and the resilient pressure with which the casing grips the main tube 2 tends to prevent rotation or" the casing. Thus the casing is normally held in secure position on the main tube but is readilyremovable it' desired.

Arranged within the long chamber enclosed by the main tube is a porcelain core 31 upon the lower portion of which, coils 32 of a suitable resistance wire are bound, the ends of the wire being brought up` as shown in Fig. 1, thru theA core and terminating in the binding posts 33 and 34; on the inside of the rear 'half of the head. rThe coils are insulated from the inner face of the main tube wall by any, suitable means, such as by a layer of mica or heat treated sodium silicate. The Contact stud 36, molded into the material of the rear portion oi' the head, is connected by conductor 37 also embedded in the material of the head with the binding post 34, and the contact stud 38, is similarly connected by the conductor 39 with a plate 4.1 molded into the surface ot' the head part. The plate 41 is provided with a stud 42 upon which is pivotally mounted the switch arm 43 which may be formed as shown in Fig. 1, and which is provided with an arcuate section le provided with` gear teeth in mesh with a pinion 16 journaled in the plate 41. The switch arm 113 at; is outer end is provided with a contact point 1 7 which is opposed to the contact point t8 on the switch arm 119 which is pivotally mounted on a stud 51 havthe saine axis as the stud 42 and extending from the plate 52 fixed on the insiclc surface of the head and in electrical contact with the bindingpost 38. A fiber washer 53 is interposed between the two studs to sep'- arate the two switch arms, which, it will be understood from the above, control the flow of energy to the heating coil. The switch arm 49 is extended past the pivot stud 51, in the arm 5-1, which is pivotally connected by means of the turn-buckle 56 with the end of the ourdon tube- 57 'which circles about the inside of the head and 'is lined on the projecting main tube portion 12 and .in communication with the pressure transit-r tube 13. The EO-UdOll tube is insulated 'from the lever arm by the block 58 formed of ii er or other non-conducting material and comprising a part of the turn-buckle 56.

Means are provided tor adjusting from the outside oi the head ot the instrument the position of the switch arm fil-3 so that the temperature at which the contact points L17 and #i8 separate, to break the circuit thru the heatingcoils, may be predetermined and means are also provided for evaluating the adjustment of the arm in terms of the teniperature at which the contact is broken. ARotatably journaled in the front part of the head isa shaft 61y slotted on its inner end, as shown, to engage the correspondingly formed end of the shaft 62 on which the pinion s6 is mounted. The outer end oitl the shaft 61 is provided with a disk 63 of bake- `lite or liber and having a pointer 6d thereon, and a spring 66 interposed between the shaft 61 and the inner face oit the casing resiliently presses the disk 63 to the head and` provides a frictional resistance to its rotation. Arranged radially about the disk 63 are indicia 67 expressing degrees of heat in accordance with the Fahrenheit Scale Vand also an oi' position in which the contacts or" the switch aims are out of engagement.

F rom the above it will be clear that movement of the disk 63 will turn the pinion 16 to vary the position of the switch arm 4:3, which is then held in position with sufficient rigidness because of the frictional engagement of all the parts. Wlith the device inscrted in a hot water bottle and the disk 63 turned to, say, 140 degrees and with a proper connection made to ay suitable source of current supply, the current Hows thru the heating coils, the hot tube transmitting the heat to the liquid in which it is immersed. With the warming up of the liquid in the bottlel the fluid in chamber 6 is volatilized, creating a pressure which is transmitted thru the tube 13 to the Bourdon tube 57 causing it to flex; outwardly. The proportion of parts is such that at the predetermined temperature of 140 degrees the lexure of the tube 57 is suliicient to break contact between the switch arms, thus interrupting the current supply and permitting the contents of the bottle to cool somewhat. As soon as the cooling processr has carried the temperature below 140 degrees, inward ieXure of the Bourdon tube effects the closing of the contact between the switch armsthus renewing the current supply. It is found that a very close regulation of the temperature of the hot water bottle may thus be obtained. Since the chamber 6 is at the extreme end of the tube from which it is separated by a neck of reduced cross section, and is theretore removed from the immediate vicinity of the heating coils as well as surrounded by the liquid in the bottle, it 'follows that the lil@ fer tube, undue heating of that tube with consequent undesirable changes in the pressure 1n the Bourdon tube are avoided.

While I have shown the stopper 16 rotatable on the tube sothat the tube as a Whole need not be rotated to seat it in the aperture of the hot Water bottle, it is obvious that the stopper portion oi my device may be rigidly formed with the tube and the entire device rotated to seat in the lling aperture.

I claim: y

l. An electric heater comprisng a tube terminating in a hollow head at one end and a bulb at the other end, an electric heating element arranged in said tube, a quantity of fluid in said bulb, a. switch for controlling the flow of current to said heating: element, fluid pressure controlled means in said-head for operating said switch, and a tube for connecting said bulb to said pressure controlled means and lying outside of said first named tube.

2. An electric heater comprising a tube terminating at one end in a bulb, an electricheating element arranged in said tube, a quantity of iluid in said bulb, a switch 'for controlling the tion' of current to said heating element, fluid pressure controlled means for operating` said switch, and an exposedV tube for connecting said bulb tosaid pressure controlled means.

3. An electric heater comprising a tube terminating at one endin a bulb, an e-lectric heating element arranged in said tube a quantity of Huid in said bulb, a pair ot pivoted switch arms, fluid pressure controlled means connected into said bulb for controlling the movement of one of said arms, means for manually adjusting the other arm, and means for energizing said said heating element. v

e. An electric heater comprising a tube terminating at one end in a bulb, an electric heating element arranged in said tube, a quantity of fluid in said bulb, a pail of pivoted switch arms, fluid pressure controlled means connected into said bulb for controlling the movement of oneolt' said arms, means for manually adjusting the other arm, means for energizing said heating element, and means lfor removably mounting said tubo in the lilling aperture of a container.

5. An electric heater comprising a tube terminating at one end in a bulb, an electric heating element arranged in said tube, a quantity of fluid in said bulb, a pair of normally engaged switch arms, fluid pressure controlled means connected With said bulb for controlling the movement of one of said arms, means forymanually adjusting the other arm, indicia 'for evaluating the adjustment in terms of the tempera-ture at which the pressure controlled means will move its associated arm to open the switch, and means for energizing the heating element. Y

In testimony whereof, have hereunto set my hand.

JOHN K. N OR-THROP. 

